Vulnerability Note VU#936529

Microsoft Jet Engine stack buffer overflow

Overview

The Microsoft Jet Engine contains a stack buffer overflow, which can allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable system.

I. Description

Microsoft Jet, or Joint Engine Technology, is a database engine that is used by several Microsoft products, including Access and Visual Basic. A Microsoft Access database uses the .MDB file extension by default. The Microsoft Jet Engine contains a stack buffer overflow in the handling of specially crafted database files.

Microsoft Word can link to Jet databases. In some cases, the database can be opened without prompting the user. This can allow Microsoft Word documents to be used as an attack vector for this vulnerability. Microsoft Outlook can also be used as an attack vector by either opening a specially crafted email message or by viewing such a message in the preview pane.

II. Impact

By convincing a user to open a specially crafted Word document or Jet database, such as a Microsoft Access .MDB file, a remote, unauthenticated attacker may be able to execute arbitrary code on a vulnerable system.

III. Solution

Apply an update

This issue is addressed in Microsoft Security Bulletin MS08-028.

Block MDB files from being processed through your mail infrastructure

To detect Jet files that have possibly been renamed to another file type, search for files with any of the following 15-byte signatures at location 0x4 (no quotes):

"Jet System DB  "
"Standard Jet DB"
"Temp Jet DB    "
"MSISAM Database"

Configure Microsoft Outlook to view and edit email messages in plain text

According to Microsoft, this can be accomplished in the following ways:

Manual (User Interaction)

Enterprise Users follow these steps to disable the Outlook feature to use Word as mail editor:

1. Restart the machine.
2. Open Outlook
3. Click Tools, click Options, and then click the Mail Format tab.
4. Clear the Use Microsoft Word to edit e-mail messages check box.
5. Clear the Use Microsoft Word to read Rich Text e-mail messages box.
6. Exit Outlook.
7. Restart the machine.

Impact of Workaround: Users will not be able to use Word as their e-mail editor or use Rich Text to read their e-mail

Using Group Policy

Domain administrators can use Group Policy to disable Word as the users e-mail editor. You do not have to restart the computer to implement this mitigation.
For information on using registry keys with a Group Policy see Using Administrative Template Files with Registry-Based Group Policy and Distributing Registry Changes.

Disable WordMail in Word 2003

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USERSoftwareMicrosoftOffice11.0OutlookOptionsMail]
"EditorPreference"=dword:00020000
"UseWordMail"=dword:00000000

Disable WordMail in Word 2002

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USERSoftwareMicrosoftOffice10.0OutlookOptionsMail]
"EditorPreference"=dword:00020000
"UseWordMail"=dword:00000000

Impact of Workaround: Users will not be able to use Word as their e-mail editor or use Rich Text by default to read their e-mail.

Restrict the Microsoft Jet Database Engine from running

To implement the workaround, enter the following command at a command prompt:

echo y| cacls "%SystemRoot%system32msjet40.dll" /E /P everyone:N

Systems Affected

Vendor	Status	Date Updated
Microsoft Corporation	Vulnerable	13-May-2008

References

http://www.kb.cert.org/vuls/id/176380
http://www.microsoft.com/technet/security/Bulletin/ms08-028.mspx
http://blogs.technet.com/msrc/archive/2008/03/24/update-msrc-blog-microsoft-security-advisory-950627.aspx
http://www.microsoft.com/technet/security/advisory/950627.mspx
http://support.microsoft.com/kb/930508
http://www.symantec.com/enterprise/security_response/weblog/2008/03/another_reason_why_microsoft_s.html
http://ruder.cdut.net/blogview.asp?logID=227
http://archives.neohapsis.com/archives/fulldisclosure/2007-11/0392.html

Credit

This vulnerability was publicly reported by cocoruder.

This document was written by Will Dormann.

Other Information

Date Public	11/16/2007
Date First Published	03/22/2008 12:32:16 PM
Date Last Updated	05/13/2008
CERT Advisory
CVE Name	CVE-2007-6026; CVE-2008-1092
US-CERT Technical Alerts
Metric	58.22
Document Revision	36